 <template>
<div class="type-nav">
    <div class="container">
      <div @mouseleave="leaveShow" @mouseenter="enterShow">
        <h2 class="all" >全部商品分类</h2>
<!-- 过渡动画 -->
<transition name="sort">
  <div class="sort" v-show="show">
          <!-- 利用事件委派与编程式导航 -->
          <div class="all-sort-list2" @click="goSearch ">
            <div
              class="item"
              v-for="(c1, index) in categoryList"
              :key="c1.categoryId"
              :class="{cur:currentIndex==index}"
            >
               
              <h3 @mouseenter="changeIndex(index)">
                <a :data-categoryName="c1.categoryName" :data-category1Id="c1.categoryId">{{ c1.categoryName }}</a>
              </h3>
              <!-- 二三级分类 -->
              <div class="item-list clearfix" :style="{display:currentIndex==index?'block':'none'}"> 
             <!-- v-for="(c2, index) in c1.categoryChild" -->
                <div
                  class="subitem"
                  v-for="c2 in c1.categoryChild"
                  :key="c2.categoryId"
                >
                  <dl class="fore">
                    <dt>
                      <a :data-categoryName="c2.categoryName" :data-category2Id="c2.categoryId">{{ c2.categoryName }}</a>
                    </dt>
                    <dd>
                      <!-- v-for="(c3, index) in c2.categoryChild" -->
                      <em
                        v-for="c3 in c2.categoryChild"
                        :key="c3.categoryId"
                      >
                        <a :data-categoryName="c3.categoryName" :data-category3Id="c3.categoryId">{{ c3.categoryName }}</a>
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
</transition>
        
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>

 
</template>

<script>
import { mapState } from "vuex";

import throttle from "lodash/throttle";

export default {
  name: "TypeNav",
  data() {
    return {
      //存储鼠标移动到哪一个上的颜色
      currentIndex: -1,
      show:true
    };
  },
  //组件挂载完毕，可以向服务器发请求
  mounted() {
    //通知vue发请求，获取数据，存储于仓库之中
    // this.$store.dispatch("categoryList")   
                       
    //当组件挂载完毕。让show变为false
    // 如果不是home组件，将typeNav隐藏
    if(this.$route.path!='/home'){
      this.show=false
    }
  },
  computed: {
    ...mapState({
      categoryList: (state) => state.home.categoryList,
    }),
  },
  methods: {
    //鼠标进入修改响应式currentindex
    // 加上节流功能

    changeIndex: throttle(function (index) {
      this.currentIndex = index;
    }, 20),
   

    //进行路由跳转的回调函数
    goSearch(event) {
      let node=event.target
      //event.target:获取到的是出发事件的元素(div、h3、a、em、dt、dl)
      
      //给a标签添加自定义属性data-categoryName,全部的字标签当中只有a标签带有自定义属性，别的标签名字----dataset纯属扯淡
      let { categoryname, category1id, category2id, category3id } =
        node.dataset;
      //第二个问题解决了：点击的到底是不是a标签（只要这个标签身上带有categoryname）一定是a标签
      //当前这个if语句：一定是a标签才会进入
      if (categoryname) {
        //准备路由跳转的参数对象
        let loction = { name: "search" };
        let query = { categoryName: categoryname };
        //一定是a标签：一级目录
        if (category1id) {
          query.category1Id = category1id;
          //一定是a标签：二级目录
        } else if (category2id) {
          query.category2Id = category2id;
          //一定是a标签：三级目录
        } else {
          query.category3Id = category3id;
        }
        //判断：如果路由跳转的时候，带有params参数，捎带传递过去
        if (this.$route.query) {
          let location={name:'search',params:{keyword:this.keyword || undefined}}
         
          //动态给location配置对象添加query属性
          location.query = query;
          //路由跳转
          this.$router.push(location);
        }
      }
    },
    // 当鼠标移入，让商品分类展示
    enterShow(){
     if(this.$route.path !='/home'){
  this.show=true;
  }
    },
    //鼠标离开商品分类列表隐藏
leaveShow(){
  this.currentIndex =-1;

  if(this.$route.path !='/home'){
  this.show=false;
  }
  
}
  },
};
</script>

<style scoped lang="less">
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
            }
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          // &:hover {
          //     .item-list {
          //         display: block;
          //     }
          // }

        }
        .cur {
          background: skyblue;
        }
      }
    }
    //过渡动画的样式
    .sort-enter{
      height: 0px;
     
    }
    .sort-enter-to{
      height: 461px;
     
    }
    //定义动画时间
    .sort-enter-active{
      transition: all .5s linear;
    }
  }
}

</style>


